Hydraulic pump with leak-preventing construction



May 6, 1941. o. JACOBSEN HYDRAULIC PUMP WITH LEAK-PREVENTINGCONSTRUCTION Filed April 17, 1939 2 Sheets-Sheet 1 we w M INVENTORPatented May 6, 1941 HYDRAULIC PUMP WITH LEAK-PREVENT- ING CONSTRUCTIONOystein Jaeobsen, Montgomery County, Ohio, as-

signor to The Duriron Company, Inc., Dayton, Ohio, a corporation of NewYork Application April r1, 1939', Serial No. 268,157

2 Claims. (Ci. 103-103) This invention relates to hydraulic pumps, andin particular, to such pumps as are employed for pumping corrosivefluids.

One object of this invention is to provide a centrifugal pump havingmeans for preventing the flaw of corrosive fluids along the drive shaftand tnrough the packing thereof.

Another object is to provide a centrifugal pump having an impellermounted on a shaft supported within a casing, this impeller having adual pumping function whereby it pumps fluid, not only from the mainbody of fluid in the pump intake chamber, but also from a chamberopposite the pump intake chamber on the other side of the impeller andadjacent the packing, which is designed to prevent leakage along thedrive shaft.

Another object is to provide a centrifugal pump, as described in thepreceding object, wherein the impeller is provided with means directlyengaging the packing and serving to further assist in the prevention ofleakage along the shaft and through the packing.

Another object is to provide a centrifugal pump having an impeller withdouble chambers pump having an impeller with a hub formed ofcorrosion-resisting material, the impeller hub being mounted upon acore, which, in turn, is mounted upon the end of the impeller driveshaft, the impeller carrying annular portion engaging a packingsurrounding a sleeve, which, in turn, surrounds the drive shaft.

Another object is to provide a centrifugal pump having a. doubleimpeller, together with equipped with vanes and separated by apartition.

Another object is to provide a centrifugal pump having an impeller withvanes enclosing separate chambers within the impeller, one set of vanechambers opening into the pump intake chamber, the other set of vanechambers opening into a leakage chamber adjacent the shaft packing, butseparated therefrom by an annular impeller portion which directlyengages the packing and furnishes additional means for the prevention ofleakage from the leakage chamber into the packing.

Another object is to provide a centrifugal pump having a hollow impellerand vanes therein enclosing separate chambers within the impeller, oneset of vane chambers opening into the pump intake chamber, the other setof vane chambers opening into a leakage chamber on the opposite side ofthe impeller, the impeller having an integral annular portion directlyengaging the packing around the drive shaft and impeding the leakage offluid by necessitating this following a labyrinthine path around theannular portion.

Another object is to provide a centrifugal pump as set forth in thepreceding object wherein the packing surrounds a sleeve, which, in turn,surrounds the drive shaft and thus protects the drive'shaft from injuryby a corrosive fluid.

Another object is to provide a centrifugal means for moving the impelleraxially to vary the width of the leakage channel between the impellerand the casing in order to vary the amount of fluid conveyed by theauxiliary portion of the impeller.

Another object is to provide a centrifugal pump as set forth in thepreceding object wherein a valve is provided in the outlet circuit ofthe pump for throttling or wholly cutting off the discharge of the pumpthereby causing the pump to become a recirculator and to recirculate anydesired portion of the liquid within the pump before discharging itthrough-the throttled outlet circuit.

In the drawings:

Figure 1 is a central longitudinal section through a preferredembodiment of the pump of this invention.

Figure 2 is an enlarged, detailed view of the impeller and adjacentstructure shown in Figure 1.

Figure 3 is a view similar to Figure 2 but shows the pump of thisinvention arranged as a recirculator and recirculating the fluid withinthe interior of the pump before completely discharging it from the pump.

General arrangement In general, the. centrifugal pump of this inventionis intended for the pumping of corrosive fluids, and particularly toprevent the flow of such corrosive fluids along the drive shaft.

Hitherto the leakage of corrosive fluids along the drive shaft ofcentrifugal pumps has caused great damage to the shaft and itsassociated structure and this action is particularly serious when acidsare being pumped and has often resulted in a complete break down of thepumping apparatus.

The present invention effectively prevents such leakage by providing ahollov impeller with the vanes thereof dividing the interior of theimpeller into two sets of vane chambers, these vane chambers beingseparated f in each other by a partition formed with the hub of theimpeller. The main set of vane chambers communicates directly with theintake passageway of the pump, whereas the auxiliary set of vanechambers communicates with the leakage chamber adjacent the pump shaftpacking. The leakage chamber is separated from this packing, however, byan annular member preferably formed integral with the impeller anddirectly engaging the packing. In this manner, any leakage of fluidcannot take place along the drive shaft and through the packing, becauseof the presence of the annular portion of the impeller. At the sametime, the auxiliary vanes of the impeller pump the leakage fluid out ofthe leakage chamber and prevent its reaching the packing by any tendencyto flow around the annular obstacle.

Construction Referring to the drawings in detail, Figure 1 shows apreferred embodiment of the pump of this invention as consisting of apump casing, or volute I, having an end plate engaged by a clamping ringl2 and secured by the bolts l3 to the frame l4. A gasket 5 preventsleakage of fluids between the casing l and the end plate I The latter isprovided with an axially extended portion 6 having an inlet chamber l1,having axially directed guide vanes I8 for preventing swirling of thefluid as it enters the impeller. The enlarged outer end l9 of the endplate H is engaged by a. clamping ring 28, forming part of a unionwith asuitable intake, or suction conduit, forming no part of the presentinvention. The outlet end 2| of the casing or volute 0 is similarlyenlarged and engaged by a similar clamping ring 22 for a similarpurpose.

The casing, or volute I6, is likewise provided with an axially extendingportion 23, containing a bore 24 with packings 25, arranged in pairs andseparated by annular spacing members 26.

The packings 25 surround a sleeve 21, which, in turn, is mounted uponthe drive shaft 28 of the pump and rotatable with it. The packings 25are compressed by a gland 29 by means of the nuts 30 mounted upon thestuds 3|.

Beyond the gland 29 the drive shaft 28 is ro tatably mounted inanti-friction bearings 32 within the frame l4, the latter being providedwith a lubricant chamber 33. Escape of lubricant isprevented by the oilseal rings 34. The frame I4 is extended downwardly to provide a base 35.

Threaded upon one end of the drive shaft 28 is a core 36 upon which ismounted the pump impeller generally designated 31. The impeller 31 isprovided with an annular enlargement 38 connected by the tubular wall 39Ito'the hub 48 of the impeller. The impeller 31 is provided with sidewalls 4| and 42, between which are arranged impeller vanes 43. The hub40 is also provided with curved surfaces 44 and 45, respectively formingmain and auxiliary passages 46 and 41 with the curved inner surfaces 48and 49 of the impeller walls 4| and 42. The curved surfaces 48 and '49are additionally rounded at 58 and respectively, so as to increase theemciency of the inward flow. The hub 40 is provided with a projectingportion 52.forming a partition separating the main vane chamber 46 fromthe auxiliary vane chamber 41. The vanes 43 are secured to thispartition 52. The volute I0 is provided at its bottom portion with adrainage port 54 closed by a cover plate 55 secured to the voluteextension 56 by means of the U-bolt 51.

In order to permit free rotation of the impeller 31, the latter isseparated a slight distance from the volute III by the spaces 58 and 59re-' spectively. The space 59 leads into the leakage chamber 60partially enclosed by the annular portion 38 of the impeller 31 andzalsoby the tubular portion 39 thereof.

Operation In the operation of the centrifugal pump of this invention thefluid enters the inlet chamber H of the end plate extension l6, and isdrawn by suction into the passageway 46 of the impeller, this suctionbeing created by the rotation of the vanes 43. The main flow of fluidthrough the inlet passageway 46 passes outwardly through the spacesbetween the vanes 43, into the marginal chamber 6| of the volute Ill,and thence into the discharge passageway of the volute l8.

During this operation, however, a certain portion of the corrosive fluidbeing pumped leaks through the space 59 into the leakage chamber 60.Meanwhile, however, the rotation of the impeller 31 and its blades 43causes a suction to be set up in the auxiliary vane chamber 41, therebypumping the leakage fluid out of the chamber 60 and likewise into themarginal chamber 6| of the volute Ill. The annular portion 38 of theimpeller hub 40 likewise rotates with the impeller 31 and prevents theescape of the corrosive fluid since it directly engages the packings 25.It will also be observed that while the impeller 31 is stationary,during periods in which the pump is not in operation, the annularenlargement 38 of the impeller 31 likewise prevents seepage of thecorrosive fluid into engagement with the pump drive shaft 28 or itssleeve 21.

Pump employed as recirculator The arrangement shown in Figure 3 isgenerally similar in construction to the form of the invention shown inFigures 1 and 2 and similar parts bear the same reference numerals. Itshould be further pointed out, however, that the drive shaft 28 isadjustable longitudinally by means of its threaded portion 65 and thethreaded member 66 engaging it. By this means the impeller 31 may bemoved inward or outward relatively to the packings 25 so as to increaseor decrease the width of the space 59. A valve 61 is provided at someconvenient point beyond the outlet of the volute l0 so that the lattermay be partially or wholly throttled. When this is done and a sufiicientspace 59 is provided by adjustment upon the drive shaft 28, the fluidentering by way of the intake conduit I1 will be recirculated throughthe passageway 46, the chamber 6|, the space 59, the leakage chamber 66,the passageway 41 and the chamber 6|, etc., repeating this recirculationone or more times depending on the amount of throttling due toadjustment of valve 61 by its adjusting member 68.

The telescoping connection 580. permits this longitudinal adjustment tobe made in order to vary the recirculation efiect yet prevents theformation of a gap between the forward end of the impeller and the endplate I In certain installations of this device, for example, it hasbeen found desirable to mix certain liquids with other substances. Forthis purpose the present modification has been found very valuable bythe provision of this recirculation feature. If the space 59 between theimpeller 31 and the casing wall is made very narrow, a comparativelysmall amount of fluid will flow through it. The wider this space 59becomes the greater will be the amount of fluid carried by it; Thus, byadjusting the amount of throttling due to the valve 61 and also byadjusting the width of the space 59 by adjustments upon the drive shaft28 the amount of recirculation can be effectively regulated.

It will be understood that I desire to comprehend within my inventionsuch modifications as come within the scope of the claims and theinvention.

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent is:

1. In a centrifugal pump, a casing having an intake chamber at one endand a cylindrical extension at the other end, an impeller adapted torotate within the casing, said impeller having a hub from which theimpeller blades radiate, a shaft contained within the casing extensionand secured to said hub, and packing material between the shaft and saidextension, said hub terminating in a portion of limited width andgreater diameter than the main portion 01 the hub, said main hub portionof smaller diameter extending from saidenlarged portion toward saidblades, whereby a sump is provided, the blades of said impeller havingtwo sets of pumping surfaces at their inner ends, one set beingpositioned adjacent the intake chamber to pump fluid from said chambertoward the periphery of the impeller and the other set being positionedadjacent said sump in order to pump fluid which collects the sump towardthe periphery of the impeller, whereby v leakage of fluid toward thepacking material is prevented.

2. In a centrifugal pump, a casing having an intake chamber at one endand a cylindrical extension at the other end, an impeller adapted torotate within the casing, said impeller having a hollow hub with anenlarged exterior portion from the blades of said impeller having twosets of pumping surfaces at their inner ends, one set being positionedadjacent the intake chamber to pump fluid from said chamber toward theperiphery of theimpeller and the other set being positioned adjacentsaid sump and extending toward the periphery of the impeller, wherebyleakage of fluid toward the packing material is prevented.

OYS'I'EIN JACOBSEN.

